As electronic and electrical components (ECs), such as diodes, light emitting diodes (LEDs), transistors, integrated circuits and multilayer integrated circuits, become more prevalent devices, EC performance becomes more critical. In most instances, EC performance is frequently limited by the EC's ability to minimize heat production and improver heat transport away from the heat generating regions to heat sinks, thereby keeping the junction temperatures and component temperatures low and diminishing thermally-generated mechanical stresses in the materials and layers making up the EC.
The diodes, transistors, etc. in ECs all have a certain amount of electrical resistance. When electrical currents flow in the ECs, heat is generated. One parameter of importance is the junction temperature, where one type of semiconductor interfaces with another type of semiconductor. This is also the location where much of the resistance is located. Heat generated at these locations impacts the performance including lifetime of the EC. Removing this heat and keeping the junction temperatures as low as possible is important for proper functioning of the EC.
Carbon nanotubes (CNTs), graphene and pyrolytic graphite can be incorporated in ECs where electrically conductive and/or semi conductive properties are desired. CNTs and graphene can also favorably affect heat transport and structural strength. However, they do not work where the material needs to be electrically insulating. Thus, CNTs have limited efficacy with respect to enhancing ECs.
Boron nitride nanotubes (BNNTs) have been considered for a number of prospective applications, such as, for example: enhancing the strength of ceramic, metal and polymer composites, functionalizing with other attached molecules for a range of chemical reactions, enhancing the thermal conductivity of certain composites, creating filters and associated mats, neutron detectors, biomedical interactions including electroporation for cancer treatment, piezoelectric devices, and electrically insulating layers in supercapacitors (also known as ultracapacitors).
High quality BNNTs, such as those manufactured by BNNT, LLC of Newport News, Va., have few defects, no catalyst impurities, 1- to 10-walls with the peak in the distribution at 2-walls and rapidly decreasing with larger number of walls. Although dimensions may vary depending on the manufacturing process, BNNT diameters typically range from 1.5 to 6 nm but may extend beyond this range, and lengths typically range from a few hundreds of nm to hundreds of microns but may extend beyond this range.
Previous patents and published applications have suggested the addition of materials including BNNTs into the materials going into ECs. See for example: U.S. Patent Publication US2014/0080954 A1 to Raman et al.; and U.S. Pat. No. 6,864,571 B2 to Arik et al. However, the methods disclosed Raman merely suggest use of BNNTs in bulk, and the methods disclosed by Arik merely suggest “generally aligned nanotubes that extend away from the catalyst layer” i.e. in the out-of-plane and similar out-of-plane heat transfer for limited aspects of the ECs. Merely dispersing or including the BNNTs into the materials going into ECs or out-of-plane thermal conductivity is insufficient to enhance the thermal management in ECs. The chemical vapor deposition (CVD) growth methods of Arik do not produce high quality BNNTs, i.e. few wall, high aspect ratio, minimal defects and catalyst free, as they take place at temperatures and nitrogen pressures far below what is required for high quality BNNTs. Indeed, Arik's use of chemical vapor deposition to form BNNTs severely limits Arik's ability to enhance ECs using BNNT group layers. What is needed are more effective methods for enhancing thermal management in ECs.